The primary function of a HVAC system is to provide thermal comfort for building occupants. Paradoxically, conventional HVAC control systems do not solicit feedback from more than one building occupant. Typically, a single thermostat or a temperature sensor is the only feedback mechanism for determining thermal comfort for a given heating zone. Moreover, the thermostat or temperature sensor may be influenced by the micro-climate around it and thus may not always reflect the human sense of comfort. In such a system, the location of the thermostat becomes extremely important in correlating the thermostat sensed temperature with the actual room air temperature. The human level of comfort has a strong correlation with the room air temperature as demonstrated by early research (Fountain, M. E., and C. Huizenga., "A Thermal Sensation Prediction Tool for Use by the Profession," ASHRAE Transaction, 1997, Vol. 103, Part 2). See, e.g., FIG. 1.
On any given day the thermostat setpoint may need adjustment depending on prevailing outdoor and indoor load conditions. For example, a mild day may require less heating whereas an unseasonably warm day may require lowering of the thermal setpoint to provide additional cooling.
Building occupants can react to the changing environment by adjusting the thermostat setpoint. However, in most large buildings a single thermostat serves an area or zone occupied by multiple occupants. Hence, it is impractical to change the thermostat setpoint manually based on the comfort level of each individual occupant. Moreover, occupant access to the thermostat is often restricted to prevent abuse. The end result is that in an existing building control system, the building occupants have limited opportunities to provide feedback.
In response to these problems, one object of the present invention is to provide an improved mechanism for determining a thermal setpoint using feedback from multiple occupants of a given heating/cooling area.
More particularly, an object of the present invention is to provide an improved HVAC system wherein many occupants may be provided with an interface for communicating thermal comfort feedback.
Another object of the present invention is to utilize an existing communications network such as Internet or Intranet to carry the feedback information to the HVAC controller in the improved system.
Another object of the present invention is to collect setpoint data, determined using occupant feedback, for subsequent use in an adaptive setpoint model for predicting a setpoint in the improved system.
Yet another object of the present invention is to provide a predicted setpoint using a neural network and historical setpoint data in the improved system.
These and other objects of the present invention are discussed or will be apparent from the following detailed description of the invention, while referring to the attached drawings.